THE HAGUE, Netherlands — Worshippers at church services across the Netherlands on Sunday prayed for the victims of the Ukraine air disaster and their next of kin, as anger built over the separatist rebels' hindering of the investigation into the downing of Malaysia Airlines Flight 17.

At the St. Vitus church in the central city of Hilversum, Father Julius Dresme summed up the nation's pain.

"It's terrible, and everybody's hearts are bleeding and crying," he said. "And it makes (people) restless and people feel sorrow, and feel a little anger but mostly sadness, confusion."

In Rome, Pope Francis led thousands of tourists and pilgrims assembled in St. Peter's Square in prayer for peace in Ukraine and the Mideast.

"I invite you to remember and to keep praying for tensions and conflicts which are going on in different parts of the world, especially in the Middle East and in Ukraine," he said.

Others mourned privately.

At the Amsterdam student rowing club Skoll, a single member sat weeping Sunday as she wrote in a condolence book for two members of the club who died, Karlijn Keijzer and her boyfriend Laurens van der Graaff.

Amid the grieving, Prime Minister Mark Rutte is pushing for Russian President Vladimir Putin to use his influence over the rebels in eastern Ukraine to ensure a full investigation into the tragedy that killed 298 passengers and crew, including 193 Dutch citizens.

Rutte angrily condemned the rebels Saturday evening for interfering with the wreckage and bodies in Ukraine.

"This is totally disgusting. It is also serious because it undermines the investigation," he said.

Rutte called Vladimir Putin on Saturday and had what he described as "an extremely intense telephone conversation" with the Russian president in which he urged him to exert his influence over the rebels and ensure there is a thorough, independent international investigation.

"I told him the time is running out to quickly show the world that he intends to help," Rutte said. "He must take the responsibility now with the rebels and show the Netherlands and the world that he is doing what is expected of him."

Best-selling Dutch newspaper De Telegraaf went further in a front-page appeal for decisive action to protect the crash site.

Under the Dutch headline, "Enough is enough," the paper called for NATO troops to be deployed in Ukraine to secure the wreckage and bodies in eastern Ukraine.

"At the same time, special forces must be deployed to track down the perpetrators of this mass murder and bring them to the Netherlands to face justice."

Also Sunday, the chief executive officer of Malaysia Airlines, Ahmad Jauhari Yahya, arrived in the Netherlands and signed a condolence book at Amsterdam's Schiphol Airport for victims of the crash.

The airline also announced it was "retiring" the flight code 17 of its Amsterdam-to-Kuala Lumpur flights "out of respect for our crew and passengers of the mentioned flight code" and replacing it from July 25 with the flight code 19.